Is it normal to wake up with an erection?

Yes. The average male will have four to five erections throughout the night. This appears to be nature’s way of keeping the penis healthy, since erections bring fresh blood, oxygen, and nutrients to the tissues of the penis. The erections are not necessarily related to sexy dreams. Another contributor to “morning wood” is testosterone. Testosterone levels naturally peak in the morning hours, which may promote both erections and sexual desire. Not having a morning erection may indicate low testosterone levels, or excess alcohol use the night before.